by
Bittinger, Marvin L.; Ellenbogen, David J.; Johnson, Barbara L.

Answer

$(x+4)(x-2)$

Work Step by Step

Grouping the first and second terms and the third and fourth terms, the given expression is equivalent to
\begin{array}{l}\require{cancel}
x^2+4x-2x-8
\\\\=
(x^2+4x)-(2x+8)
.\end{array}
Factoring the $GCF$ in each group results to
\begin{array}{l}\require{cancel}
x(x+4)-2(x+4)
.\end{array}
Factoring the $GCF=
(x+4)
$ of the entire expression above results to
\begin{array}{l}\require{cancel}
(x+4)(x-2)
.\end{array}